Centrifugal pump



Aug. l, 1967 R B, CQVALT ET AL CENTRIFUGAL PUMP Filed Dec. 17, 1965 f @M6 67W C@ /7 /36 United States Patent O 3,333,545' CENTRIFUGAL PUMP Robert B.V Covalt, McHenry, Ill., and Karl J. Holf and` This invention relates to aA centrifugal pump and more particularly to a centrifugal pump designed to prevent fouling or seizing of the pump mechanism whenv pumping liquids containing high concentrations of dis- .persed solids.

Conventional centrifugal pumps are usually equipped with a stuffing box, a drive shaft carrying an impeller,

and an impeller chamber through which liquid is ex-V pelled. The drive shaft extends through the stuingbox or sealing mechanism and into the impeller chamber. Pressure packings are employed in the stuing box to provide a duid-tight engagement with the shaft. However, pressure packings impose a frictional drag on'the shaft and wear with use to provide an imperfect seal and thereby impair the eiciency of the pump. More importantly, in centrifugal pumps of conventional design, the shaft bearings and sealing mechanism are exposed to the liquid being pumped. The liquid contacts or splashes against the shaft bearings and sealing mechanismto cause fouling or seizing of the pump shaft, depending on the type of liquid being pumped.

It would therefore be desirable to provide a centrifugal pump which obviates the above described disadvantages.

It is therefore an object of the present invention to provide a non-fouling centrifugal pump foreliiciently pumping liquids and slurries which normally foul centrifugal-type pumps equipped with standard seals or stuing boxes.

It is another object of the present invention to provide a centrifugal pump for etiicient-ly pumping liquids and slurries which normally foul centrifugal-type pumps which pump prevents contact between the liquid 'being pumped and the sealing mechanism of the pump.

. Itis a further object of the present invention to provide.a centrifugal pump Construction employingga rotary shaft carrying an impeller, whichl pump construction precludes contact between the liquid being pumped and the bearings used to support 'the shaftof'the'pump.

It is a further object of the present invention to provide a centrifugal pump Which'accomplishes the aforementioned objects in a simple and leconomical manner.

Broadly, the above and other objects are attained by the present invention which embodies among its features an upright.cylind.rical pump. casing deningV respectively at its upper portion a generally air-.tightpumpchamber and at its lower portion an impeller chamber. A' rotary shaft carrying an impeller on its lower end is centrally disposed and rotatably mounted within the casing, the impeller occupying said impeller chamber.

A liquid-accumulating chamber is mounted on the pump casing at a position intermediate the impeller chamber and the upper portion of the pump casing, said accumulating chamber being in communication with the pump chamber through a plural-ity of spaced apertures or ports on the pump casing. A sealing mechanism surmounts the pump casing and is in air-tight contact therewith. The sealing mechanism preferably comprises a conventional double water ush seal although other seals are operable. Within the sealing mechanism, a rotary ring rotates with the shaft and contacts a fixed ring. The tolerances are such that a very small amount of sealing uid exits through the seal faces. Two main bearing-s in engagement with the shaft are located at a position exterior'ofthe pump casing andofthesealingV mechanism. A uid inlet port-is provided on the pump casing at a position exterior of the sealing mechanismand-ata position intermediate the accumulating chamber and the impeller chamber. A uid outletport is provided on the impeller chamber. In operation, the Iinlet port of the pump is connected `to a container holdin-g the fluid to .be pumped. AsV the uid ows from its containerand rises within the pump chamber, the rising fluid com-- preses the air within the chamber. The head of compressed airso formed provides abutler or cushion between the sealing mechanism and the liquid being pumped, thereby eiectively preventingcontact between the Vliquid and both -the sealing mechanism and the bearings. Rotation of the shaft with its attached impeller forces the intake liquid through Vthe outlet port to any desired location. v

Referring now to the drawings:

FIG. lis a partial'sectional view of the novel pump,

v A to Tank B.

Referring to FIG. 1, the pump is represented gen' erally by the. reference numeral 10 andcomprises an elongate generally cylindrical, vertically disposed housingor casing 12 defining a' pump chamber 14. Housing or casing 12`terminates as its bottom port-ion 14b in ange 13a cylindrical concentric impeller casing 13 which defines impeller chamber 15 having a generally greater diameter than pumpV chamber 14n Pump cham-ber 14is sealed at its upper extremity 14a byl air-tightvcontact with sealing mechanism 24. Rotary shaft 20 'is centrallyy disposed within chamber` 14 and impeller chamber 15; respectively, and carries impeller 221on its lower extremity. The lower extremity of 'shaft=20 terminates inl close proximity to, but not in contact with the lower surface 13b ofcasing 13, the space therebetween represented by numeral 17 'being of the order of magnitude of vabout one-sixteenth of an inch. The upper extremity 20a of shaft 20f is operatively connected to motor 21 (shown in FIG.' 3). Sealing mechanism 24 surmounting casing 12 is a-doublewater flush. seal having ,a Water inlet `3'4 and outlet 36. A rotary seal 25 is also mounted insealing mechanism 24 and surroundsshaft 20 .in concentricmanner, the sea-1 face being .in extremely close proximity to; but not in contact with shaft 20. The clearance between the seal face of sealing mechanism 24vand'shaft 201s sufficiently narrow to substantially prevent the passage of water or air therethrough. v

The use of a double-"water flush lsealinstead of con ventional pressure packing which bears directly upon the rot-ary shaft eliminates frictional drag and wear on the packing with eventual loss in the effectiveness of the seal.

Bearings 50 and 52, respectively, support shaft 20 as indicated at .positions on the shaft which are exterior of sealing mechanism 24. There is no bearing contacting shaft 20 within the impe-ller chamber so that binding or seizing of the shaft by solid matter depositing on or -around the bearing is prevented. Bearings 50 and 52 are the only bearings employed in the apparatus of the present invention and their positioning exteriorly of the sealing mechanism and the pump chamber prevents seizing or binding of the shaft during operation Where slurries orV liquids containing high proportions of solids are being pumped and are likely to deposit on surfaces.

Fluid inlet 16 is located at the lower portion of casing 12 intermediate sealing mechanism 24 and impeller cas- Patented Aug. l, 1'967.

ing13. Outlet 18 is located on impeller casing 1,3y adjacent impeller 22. Outlet 18 is generally of smaller diameter than inlet 16. Inlet 16 and outlet 18 may be conveniently threaded to receive standard screw threaded pipe fittings. A cylindrical liquid accumulating chamber 46 defining liquid accumulating reservoir 47 is mounted on casing 12 at'a position intermediate inlet 16 and sealing mechanism 24. Accumulating chamber 46 is in Vcommunication with pump chamber 14 through a plurality of spaced apertures or ports 48 in Ycasing 12. Accumulating chamber 46 is equipped with cleaning plugs 49 and -1 which permit easy access to the chamber 47 for cleaning after extended use. Brackets 53 and 54 are conveniently provided for mounting the pump in a desired place. Liquid accumulating chamber 46 functions as an additional reservoir for receiving the liquid being pumped, thereby increasing the capacity of Ipump chamber 14 Without an increase in the length of the pump casing which would require a correspondingly longer rotary shaft. A shorter shaft is desirable to obviate vibration or Wobbling of Ithe shaft under high load and torque conditions of use. The use of an accumulating chamber also permits the attainment of a greater volume of compressed air for a given pressure 'between sealing mechanism 24 and the liquid being pumped. Sight tube 55 of `clear plastic or glass is conveniently mounted in communication Vwith accumulating chamber 46 and the upper portion of pump chamber 14 and serves as a safety device for detecting leaks in sealing mechanism 24.

It isunderstod that when lpumping fluids other than Water, it may be convenient to use as sealing ui-d a liquid compatible with that which is being pumped so that any small amount of seepage of sealing Huid through the seal into lpump chamberr14 will pose no contamination problem. It is also possible to utilize .air pressure as the'sealing medium and in certain instances it is convenient to do so. Y

Referring to FIG. 3, there is schematically shown the described pump in vertical position and operatively connected between reservoirs A and B to convey contents of vessel A through line 62, pump 10 and line 63 to reservoir or tank B in that sequence. Lines 64 and 65 are respectively inlet and outlet feed lines to sealing mechanism 24. Y

While one particular embodiment of this invention is shown, it will be understood, yof course, that the invention is not to be limited thereto, since many modiiications may be made, and it is contemplated therefore by the appended claims to cover any such modifications as fall within the true spirit and scope of this invention.

' We claim:

1. A centrifugal pump for operation in an upright position and adapted to pumping liquids containing high concentrations of dispersed solid-s comprising an elongate upright casing defining at its upper portion a pump chamber and at its lower portion an impeller chamber, said casing having a ui-d inlet port adjacent the impeller chamber and a uid outlet port within said impeller chamber, lsaid casing further having a plurality of spaced apertures intermediate its upper and lower portion, a driven rotary shaft centrally disposed within said casing, said shaft carrying an impeller on its lower extremity, and disposed within said impeller chamber; sealing means surmounting and exterior of said casing, said means being in essentially fluid tight engagement with said shaft, and an accumulating chamber mounted on said casing at a position intermediate the impeller chamber and the sealing mechanism, said accumulating chamber being in communication with the pump chamber through said plurality of spa-ced apertures in said casing, said pump in operation providing a cushion of compressed air in the upper portion of said pump chamber above the level of uid being transmitted by the pump.

2. The centrifugal pump of claim 1 wherein the sealing means is a circulating water seal.

3, The centrifugal pump of claim 1 wherein the impeller is disposed in spaced close proximity to the bottom of the impeller chamber.

4. The centrifugal pump of claim 1 wherein the pump chamber is of .generally cylindrical configuration having its axis vertically oriented.

5. A centrifugal pump for operation in an upright position and adapted for pumping uids Vhaving a high concentration of dispersed solids comprising an elongate vertical oriented pump chamber including an impeller chamber and associated outlet means at the lower end thereof, an inlet port spaced above the impeller chamber, accumulator chamber means spaced above the in let means and communicating with said pump chamber, a pump shaft rotatably and vertically disposed within the pump chamber having impellerV means at the one end thereof disposed in the impeller chamber and the other end extending upwardly outwardly of the pump chamber, and a shaft and pump sealing means at the upper end of said pum-p chamber, said pump in operation being adapted to receive and drive uid through the inlet port, impeller chamber and outlet port, and maintain a cushion of compressed =air in the upper portion of the pump chamber above the level Iof liquid in the pump and associated accumulator chamber.

References Cited UNITED STATES PATENTS 1,883,266 10/ 1932 Yoder 103-87 2,304,849 12/ 1942 Ruthman 103-87 2,525,370V 10/ 1950 Pollak 103-87 3,157,128 11/1964 Hustinx 103-87 FOREIGN PATENTS 906,008 4/ 1945 France.

851,597 10/ 1952 Germany.

123,743 2/ 1919 Great Britain.

300,283 3/ 1929 Great Britain.

399,191 3/ 1966 Switzerland.

lDONLEY J. STOCKING, Primary Examiner.

H. F. RADUAZO, Examiner. 

1. A CENTRIFUGAL PUMP FOR OPERATION IN AN UPRIGHT POSITION AND ADAPTED TO PUMPING LIQUIDS CONTAINING HIGH CONCENTRATIONS OF DISPERSED SOLIDS COMPRISING AN ELONGATE UPRIGHT CASING DEFINING AT ITS UPPER PORTION A PUMP CHAMBER AND AT ITS LOWER PORTION AN IMPELLER CHAMBER, SAID CASING HAVING A FLUID INLET PORT ADJACENT THE IMPELLER CHAMBER AND A FLUID OUTLET PORT WITHIN SAID IMPELLER CHAMBER, SAID CASING FURTHER HAVING A PLURALITY OF SPACED APERTURES INTERMEDIATE ITS UPPER AND LOWER PORTION, A DRIVEN ROTARY SHAFT CENTRALLY DISPOSED WITHIN SAID CASING, SAID SHAFT CARRYING AN IMPELLER ON ITS LOWER EXTREMITY, AND DISPOSED WITHIN SAID IMPELLER CHAMBER; SEALING MEANS SURMOUNTING AND EXTERIOR OF SAID CASING, SAID MEANS BEING IN ESSENTIALLY FLUID TIGHT ENGAGEMENT WITH SAID SHAFT, AND AN ACCUMULATING CHAMBER MOUNTED ON SAID CASING AT A POSITION INTERMEDIATE THE IMPELLER CHAMBER AND THE SEALING MECHANISM, SAID ACCUMULATING CHAMBER BEING IN COMMUNICATION WITH THE PUMP CHAMBER THROUGH SAID PLURALITY OF SPACED APERTURES IN SAID CASING, SAID PUMP IN OPERATION PROVIDING A CUSHION OF COMPRESSED AIR IN THE UPPER PORTION OF SAID PUMP CHAMBRE ABOVE THE LEVEL OF FLUID BEING TRANSMITTED BY THE PUMP. 